Fabrication of nanocrystalline Sc2O3-Y2O3 solid solution ceramics by spark plasma sintering

Sc2O3-Y2O3 solid solution (SYSS) ceramics with novel nanocrystalline structures have been successfully fabricated by spark plasma sintering (SPS) method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR and indentation techniques. The SYSS ceramics can possess high hardness by keeping their excellent infrared transmission performance. Especially, the transmittance of as-obtained SYSS ceramics can exceed as high as 80% in the infrared region of 2-6 mu m. Moreover, the Vickers hardness is increased to 9.18 GPa by increasing the addition ratio of Sc2O3 to 20 at%. Here, it is very important to point out that the mechanical strength of yttria ceramics can be evidently enhanced without deteriorating their optical transmission performance by the addition of Sc2O3 as well as the application of SPS technique, where the solid solution strengthening and fine grain strengthening are involved during the synthesis process, respectively.